The Court, in granting cert., actually said that it will decide two questions: (1) does the 14th Amendment require all states to permit same-sex marriages, and (2) does the Full Faith and Credit Clause require all states to recognize same-sex marriages performed in other states. Question 2 is irrelevant if the Court answers question 1 "yes." So, my own bet is that: the Court will answer question 1 "no" but will answer question 2 "yes"; and that both rulings will be 5-4, with Kennedy in the majority in both.
In effect, this will legalize same-sex marriage in all 50 states, but it will require gays in states like Oklahoma to travel out-of-state to have the ceremony performed; Oklahoma will then have to recognize their marriage when they return. This will permit Kennedy to both legalize same-sex marriage everywhere while still saying that he hasn't abandoned states' rights.
And therein lies the rub, no?: ‘to PERMIT same-sex’. If it’s a Right, there is no thought to needing a license. I was surprised the ‘logic’ in the Heller decision re: the 2nd; which is still being perverted (no pun intended) to this day.
If the 14th and the Full Faith require same-sex marriage, then, logically We the People all have Constitutional carry, any ‘licensed’ professional in one State may practice in another, illegal drivers licenses are valid in all 50 States, etc.